Dirac quasinormal modes in spherically symmetric regular black holes

TL;DR

This paper investigates the quasinormal modes of Dirac fields in spherically symmetric regular black holes using WKB and expansion methods, revealing relationships between frequencies and parameters, and improving numerical techniques for massive fields.

Contribution

It introduces an expansion method for QNM calculations in inverse powers of angular momentum and enhances finite difference methods for massive Dirac fields in regular black hole spacetimes.

Findings

QNM frequencies depend on angular momentum, monopole charge, and field mass.

Expansion method provides accurate QNM estimates for large angular momentum.

Improved finite difference method enables better analysis of massive Dirac field evolution.

Abstract

Using the WKB approximation, massless and massive Dirac quasinormal modes (QNMs) are studied in spherically symmetric regular spacetimes. We analyze the relationships between QNM frequencies and the parameters (angular momentum number $l$, magnetic monopole charge $\beta$ and the mass of the field $m$), and discuss the extreme charge of magnetic monopole $\beta_{e}$ for spherically symmetric regular black holes (BHs). Furthermore, we apply an expansion method to expand QNMs in inverse powers of $L=l+1/2$, and confirm good precision with $l>n$. Finally, we improve traditional finite difference method to be available in massive Dirac case, and illuminate the dynamical evolution of massive Dirac field.